title: Extractive bioconversion of cyclodextrins by Bacillus cereus cyclodextrin glycosyltransferase in aqueous two-phase system.
abstract: An extractive bioconversion with Bacillus cereus cyclodextrin glycosyltransferase (CGTase, EC 2.4.1.19) in aqueous two-phase system (ATPS) was investigated for the synthesis and recovery of cyclodextrins (CDs). Optimum condition for the extractive bioconversion of CDs was achieved in ATPS consisted of 7.7% (w/w) polyethylene glycol (PEG) 20,000 and 10.3% (w/w) dextran T500 with volume ratio (VR) of 4.0. Enzymatic conversion of starch occurred mainly in dextran-rich bottom phase whereas the product, CDs was transferred to top phase and a higher partition coefficient of CDs was achieved. Repetitive batch of CDs synthesis was employed by replenishment of the top phase components and addition of starch every 8h. An average total CDs concentration of 13.7 mg/mL, (4.77 mg/mLα-CD, 5.02 mg/mLβ-CD and 3.91 mg/mLγ-CD) was recovered in the top phase of PEG 20,000/dextran T500 ATPS. This study showed the effectiveness of ATPS application in extractive bioconversion of CDs synthesis with B. cereus CGTase.
authors.affiliation: Department of Process and Food Engineering, Faculty of Engineering, Universiti Putra Malaysia, 43400 UPM Serdang, Selangor, Malaysia.
authors.forename: Hui Suan
authors.initials: HS
authors.lastname: Ng
authors.forename: Chien Wei
authors.initials: CW
authors.lastname: Ooi
authors.forename: Mohd Noriznan
authors.initials: MN
authors.lastname: Mokhtar
authors.forename: Pau Loke
authors.initials: PL
authors.lastname: Show
authors.forename: Arbakariya
authors.initials: A
authors.lastname: Ariff
authors.forename: Joo Shun
authors.initials: JS
authors.lastname: Tan
authors.forename: Eng-Poh
authors.initials: EP
authors.lastname: Ng
authors.forename: Tau Chuan
authors.initials: TC
authors.lastname: Ling
mesh_terms: D001409:Bacillus cereus / Q000378:metabolism*; D003505:Cyclodextrins / Q000378:metabolism*; D005964:Glucosyltransferases / Q000378:metabolism*; D014867:Water / Q000737:chemistry*
chemical_list: D003505:Cyclodextrins; D014867:Water; D005964:Glucosyltransferases; C019963:cyclomaltodextrin glucanotransferase
keywords: Aqueous two-phase system; Bacillus cereus; Cyclodextrin; Cyclodextrin glycosyltransferase; Extractive bioconversion